| ( | 450 | + | x | ) | ÷ | ( | 1500 | + | x | ) | = | 51 100 |
| Multiply both sides of the equation by: | ( | 1500 | + | x | ) |
| ( | 450 | + | x | ) | = | 51 100 | ( | 1500 | + | x | ) |
| 450 | + | x | = | 51 100 | ( | 1500 | + | x | ) |
| 450 | + | x | = | 51 100 | × | 1500 | + | 51 100 | x |
| 450 | + | x | = | 765 | + | 51 100 | x |
| x | − | 51 100 | x | = | 765 | − | 450 |
49 100 | x | = | 765 | − | 450 |
49 100 | x | = | 315 |
| x | = | 315 | ÷ | 49 100 |
| = | 315 | × | 100 49 |
| = | 45 | × | 100 7 |
| x | = | 4500 7 |
| x | = | 642.857143 |